Machine for mixing asphalt



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`G. L. PEABODY.l MACHINE IOR MIXING ASPHALT.

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MAHINB FOB. MIXING ASPHALT.

No. 405.499. Patented June v18, 1889.

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' G. L. PEABODY.

MACHINE FOR MIXING ASPHALT.

No. 405,499. Patented June 18, 1889.

WITN ESSES UNITED STATES PATENT OFFICE.

GEORGE L. PEABODY, OF PITTSBURG, PENNSYLVANIA.

MACHINE FOR IVIIXING ASPHALT.

SPECIFICATION forming part of Letters Patent No. 405,499, dated June 18, 18819. Application fled October l, 1888. Serial-No. 286,853I (No model.)

To @ZZ whoml it may concern:

Be it known that I, GEORGE L. PEABODY, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Machines for Mixing Asphalt, of which improvements the following is a specification.

My invention relates to machines for melting and mixing ropk-asphaltwith other materials preparatory to laying it in pavements, and its object is to provide a simple and compact portable apparatus in which the heat required for maintaining the materials in a liqueed condition may be effectively and economically applied for such purpose and further utilized in the generation of steam for the rotation of a mixer shaft and blades, as well as to afford convenient means for cleaning the mixingchamber from time to time, as may befdesired.

To this end, my improvements consist in certain novel devices and combinations, hereinafter fully set forth.

In the accompanying drawings, Figure 1 is a vertical longitudinal central section through a machine for mixing asphalt embodying my invention; Fig. 2, a plan or top view of the same, with the cover of the mixing-chamber removed; and Figs. 3 and 4, vertical transverse sections, on an enlarged scale, at the lines x and y y, respectively, of Fig. 1.

In the practice of my invention I provide aframe 1, which is preferably formed of channel-bars, and is supported adjacent to its rear upon a pair of wheels 2, fitted to rotate upon end journals 3n on 4 an axle 3, fixed to the frame, its front end being carried upon a pair of wheels 4 of smaller diameter, mounted in a truck or swiveling frame 5, j ournaled by a pivot G to a forward extension of the frame, and provided with a tongue 7, by which the machine may be hauled from place to place. A semi cylindrical mixing chamber 8, of boiler-iron, is connected to and closes at top a furnace 9, the sides of which are inwardly and downwardly tapered, passing inside the longitudinal bars of the frame and fitting between and above the inclined lateral and horizontal central portions of the axle 3, which is bent downwardly between its journals to embrace and support the furnace. A grate 10 is supported on bearers 11 in the bottom of the furnace below the central portion of the mixing-chamber, the inwardly-tapering sides of which enable the wheels 2 to be placed as closely together' as practicable, so as to economize space, while providing a direct application of heat to the thickest body of material in the mixing-chamber.

The furnace is closed at its ends by heads 12 13, which are bolted to the side bars of the frame 1 and is secured at top to angleirons 14, connected to the heads. An opening in the rear head 12, closed by a fire-door l5, serves for the introduction of fuel, and access may also be had to the forward portion of the furnace and grate through an opening in the front head 13, closed by a door 13, The products of combustion pass off through an opening 1G in the front head 13, communicating with a discharge-line 17, which in turn communicates with the fire-chamber and ilue of a steam-boiler 1S, to be presently described.

In order to utilize the heat developed by the combustion of the fuel in the furnace in the generation of steam for the rotation of a mixer shaft and blades, a water-chamber 19 is formed in each of the furnacefheads 12 12, and a series of tubes 20, arranged one above another and connected at their ends to said chambers, is located on each side of the furnace. Said chambers and tubes are supplied with water by a pump or injector, and the direct heat of the fuel being exerted thereon a circulation of the water through the tubes is maintained and the generation of steam thereby advantageously effected.

The steam-boiler 1S, which is preferably of the vertical cylindrical type, is mounted upon abcd-casting 21, secured to the front head 13 of the furnace and to the frame and inclosing the discharge-flue 17 of the furnace. A tilting or dumping grate 22 is pivoted to the bed-casting 21 above an opening in the upper plate thereof, communicating with a central firechamber 23 in the boiler, from the y top of which chamber a iiue 24E leads to and out of the top of the boiler. A stack 2.5 may be added, if deemed desirable, to afford increased hinged to the top of the boiler, as shown, so as to be lowered for convenience in the trans- IOO draft, and in such case the stack is preferably portation of the machine. The boiler is provided with a fire-door 26, and a door 27, closing an opening in the lower plate of the bed casting 21, admits of fuel or ashes being dumped from the [ire-chamber, when required.

In order to prevent the application of an unduly high degree of heat to the water in the boiler by the escaping products of combustion, the fiue 24 is inclosed by a conical shield 47, which is open at top, so as to provide a steam-space around the iiue and prevent the contact of water therewith. The Water-chamber 19 of the front furnace-head is connected by delivery-pipes 28 with the Water-space of the boiler, into which said pipes discharge the heated water from the circulating-tubes 20.

A longitudinal mixer-shaft 29, having a worin-wheel 30 secured upon one of its ends, is mounted concentrically with the mixingchamber 8 in bearings 31 secured to the heads 12 and 13 of the furnace, and carries a series of radial stirrer-arms 32, each of which has secured upon its outer end two or more blades The mixer-shaft is preferably formed of square or rectangular section and the stirrerarms in two parts, which are bolted together to embrace the shaft. The arms are arranged helically upon the shaft-that is to say, each succeeding arm stands at an angle, say, ninety degreesin advance of the preceding' arin,so that the arms and blades act successively upon the ngaterial in the mixing-chamber in the r0- tation of the mixer-shaft. An opening closed by a valve or gate 34 is formed in the rear end of the mixing-chamber in line with its bottom, to admit of the Withdrawal of the mixed asphalt from time to time, as required, through a discharge spout 35, and to enable the chamber to be entirely cleared of material when desired without opening its doors or stopping the rotation of the mixer-shaf t, the blades 33 nearest to the outer ends of the stirrer arms, which in their traverse move as closely as may be to the wall of the mixing-chamber, are inclined relatively to the longitudinal planes of their respective arms, so as to remove the material adhering to the chamber and carry it baekwardly to the dischargespout. The blades 33 of the stirrer-arins which are next the outer ones are inclined in opposite direction thereto, and thereby tend to move'the material in opposite direction to said outer blades-that is to say, away from the discharge-spout. It will thus be seen that during the mixing operation, in which both blades of each stirrer-arm are completely submerged, the tendency of each blade to induce longit-udinal movement of the material in the mixing-chamber is counteracted by that of the other; but when so much of theI lter is unopposed, and they therefore sweep out of the chamber the remaining portion of t-he material, the removal of which has heretofore been required to be effected by hand and has involved considerable delay and inconvenience. The central portion of the mixing-chamber is closed at top by a segmental cover 3G, between which and the sides of the chamber substantially continuous open spaces are interposed, said spaces being closed on each side by a series of doors 37, which are hinged or pivoted tothe cover 36 and immediately adjoin each other, so that by raising the doors the Whole or any desired portion of the space between the cover and mixingchamber may be exposed to afford access to the interior of the latter. The vapors evolved from the materials in the mixing-chamber are carried off by an. escape-pipe 3S, which leads into the boiler-flue 24 and may be provided with a valve or damper 39.

Rotation is imparted to the mixer-shaft by an engine 40 of any suitable and preferred construction, which is secured upon the bedcasting 21 and frame 1, and is supplied with steam by a pipe 41, leading from the boiler 1S. The crank-shaft 42 of the engine carries a Worm 43, which meshes with the Wormwheel 30of the mixer-shaft, the worm 43 fitting loosely upon the crank-shaft and being caused to rotate therewith, as desired, to impart rotation to the mixer-shaft, by a clutch 44, which is adapted to slide upon a feather on the crank-shaft and is engaged With and disengaged from the worm by a lever 45. The crank-shaft also carries a loose driving-pulley 4G, which may be caused to rotate with or allowed to remain loose' upon the shaft, as desired, by the clutch 44, according as the the latter is engaged with or disengaged from the Worm 43. The engine maybe thus adapted to drive other machinery during such periods as the mixer-shaft may not be required to be rotated.

In the operation of the machine, the circulating-tubes, water-chambers, and boiler being supplied with water to a proper level in the latter, the materials to bemixed-usually consisting of rock-asphalt, Trinidad asphalt, bitumen, and coarse sand in proper proportionsare placed in the mixing-chamber and steam is generated from fuel placed in the fire-chamber of the boiler and in the furnace 9, and the asphalt is liquefied by the heat of the furnace. rlhe mixer-shaft is then rotated by the engine, and when the materials have been properly mixed the compound is removed through the discharge-opening and discharge-spout. After steam has been raised to a sufficient pressure to operate the engine, the supply of fuel to the fire-chamber of the boiler is discontinued and the cinders discharged therefrom by dumping the grate. The generation of steam is thereafter continued'by the calorific action of the fuel in the furnace 9 and of the heated products of combustion therefrom, which traverse the discharge-flue 17, fire-chamber 23, and boiler-line 24 in their exit from the furnace. The escape of waste heat is thus prevented and a IOO IIO

corresponding economy of fuel attained. The construction and arrangement of the stirrer arms and blades enables the materials to be thoroughly mixed and the chamber to be entirely cleared, when necessary, Without the inconvenience,heretofore experienced, of doing so by hand. During such periods, as it may not be necessary or convenient to operate the mixer-shaft, the engine may be employed in other duty connected with the operation of the machine, such as grinding or crushing material, pumping Water, dac.

I claim as my invention and desire to secure by Letters Patent;

l. In a machine for mixing asphalt, the combination of a furnace, a mixing-chamber located above said furnace, a steam-boiler, a discharge-flue connecting the furnace with the flue of said boiler, and a shield inclosing the boiler-line within the Water-space of the boiler, substantially as set forth.

2. In a machine for mixing asphalt, the combination of a furnace, a mixing-chamber located above said furnace, a steam-boiler, a discharge-flue leading from the furnace to the fire-chamber of the boiler, and a tilting or dumping grate located in the fire-chamberof the boiler, substantially as set forth.

3. In a machine for mixing asphalt, the combination of a mixing-chamber, a furnace located below said chamber, heads closing the ends of the furnace and having Waterchambers formed therein, and circulatingtubes Within the sides of the furnace and connecting said Water-chambers of the furnace substantially as set forth.

4. In a machine for mixing asphalt, the combination of a mixing-chamber, a mixershaft j ournaled to rotate therein, and a series of stirrer-arms secured radially upon the shaft, each arm carrying adjacent to its outer end a pair of blades which are inclined in. respectively opposite directions to the longitudinal plane of the arm, substantially as set forth.

5. In a machine for mixing asphalt, the combination of a furnace, a mixing-chamber located above said furnace, a steam-boiler, and a vapor-discharge pipe leading from the mixing-chamber to the flue of said boiler, substantially as set forth.

6. In a machine for mixing asphalt, the combination of a Wheeled supporting-frame, a furnace, a mixing-chamber, a mixer-shaft provided With stirrer-arms and fitted to rotate Witnesses:

J. SNOWDEN BELL, E. J. SMAIL. 

